3.3.2. Influence of Living Space Changing on ESDR

Living space had a significant negative influence (*p* < 0.01) on water yield service, grain production service, and carbon sequestration service (Figure 6c). For water production services, when the ratio of living space was greater than 31.35%, there was a deficit. This means that the water yield service supply was greater than the demand if the ratio of living space was less than 31.35%. For the carbon sequestration service and grain production service, this threshold was 15.68% and 44.39%, respectively.

Although the ESDR of living space on soil conservation services was negative, the trend was not strong (k = −0.01) and explained only part of the variation in soil conservation services (R<sup>2</sup> = 0.45). The influence of the living space ratio was not significant, i.e., the soil conservation service was in surplus for any value of the living space ratio between 0–100%. In summary, the living space ratio between 0–15.68% is needed to ensure that all ecosystem services are in surplus in the study area. Due to the limited number of ES selected in this

study, this resulted in a significant negative effect of living space on all ES. For some ES, such as landscape aesthetics, there is a dependence on living space, and too little living space will inevitably affect the supply of these ES.

#### 3.3.3. Influence of Ecological Space Changing on ESDR

Ecological space had a significant positive influence on water yield service, soil conservation service, and carbon sequestration service during the period 2000–2018 (Figure 6b). Ecological space explained most of the variation in the ESDR for the soil conservation service and carbon sequestration service, at 78% and 86%, respectively. When the ecological space ratio was less than 29.79%, the carbon sequestration service was a deficit. This threshold did not exist for water yield service or soil conservation service. The ESDR of ecological space on grain production service was negative (*p* < 0.01). When the ecological space ratio was greater than 88.61%, there was a deficit in the grain production service. In summary, an ecological space ratio of 29.79% to 88.61% is needed to ensure that all ecosystem services are in surplus. However, this does not mean that ecological space can be expanded indefinitely, as too much ecological space can squeeze the original production space and lead to a deficit in grain production service.
